NM_020166.5:c.1679dupA

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_020166.5(MCCC1):c.1679dupA(p.Asn560LysfsTer10) variant causes a frameshift, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000132 in 151,932 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

MCCC1
NM_020166.5 frameshift, splice_region

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 0.547

Publications

1 publications found

Variant links:

Genes affected

MCCC1 (HGNC:6936): (methylcrotonyl-CoA carboxylase subunit 1) This gene encodes the large subunit of 3-methylcrotonyl-CoA carboxylase. This enzyme functions as a heterodimer and catalyzes the carboxylation of 3-methylcrotonyl-CoA to form 3-methylglutaconyl-CoA. Mutations in this gene are associated with 3-Methylcrotonylglycinuria, an autosomal recessive disorder of leucine catabolism. [provided by RefSeq, Jul 2008]

MCCC1 Gene-Disease associations (from GenCC):

3-methylcrotonyl-CoA carboxylase 1 deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
3-methylcrotonyl-CoA carboxylase deficiency
Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen

MCCC1 links:

LOC124906309 (HGNC:):

LOC124906309 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 3-183033992-G-GT is Pathogenic according to our data. Variant chr3-183033992-G-GT is described in ClinVar as Pathogenic. ClinVar VariationId is 542948.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MCCC1	NM_020166.5 link	c.1679dupA	p.Asn560LysfsTer10	frameshift_variant, splice_region_variant	Exon 14 of 19	ENST00000265594.9	NP_064551.3	Q96RQ3A0A0S2Z693

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MCCC1	ENST00000265594.9 link	c.1679dupA	p.Asn560LysfsTer10	frameshift_variant, splice_region_variant	Exon 14 of 19	1	NM_020166.5	ENSP00000265594.4		Q96RQ3

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151932

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000384

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000139

AC:

AN:

1441672

Hom.:

Cov.:

AF XY:

0.00000278

AC XY:

AN XY:

718534

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33038

American (AMR)

AF:

0.00

AC:

AN:

44686

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26026

East Asian (EAS)

AF:

0.00

AC:

AN:

39584

South Asian (SAS)

AF:

0.0000117

AC:

AN:

85822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52864

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5262

European-Non Finnish (NFE)

AF:

9.14e-7

AC:

AN:

1094690

Other (OTH)

AF:

0.00

AC:

AN:

59700

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0448430), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.350

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000132

AC:

AN:

151932

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74194

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41328

American (AMR)

AF:

0.00

AC:

AN:

15234

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000384

AC:

AN:

5204

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10538

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68016

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.450

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

3-methylcrotonyl-CoA carboxylase 1 deficiency

Pathogenic:4

Sep 09, 2021

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Feb 01, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Asn560Lysfs*10) in the MCCC1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MCCC1 are known to be pathogenic (PMID: 11181649, 15359379, 22642865). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with 3-methylcrotonyl-CoA carboxylase deficiency (PMID: 24078573, 25382614; Invitae). This variant is also known as c.1680insA. ClinVar contains an entry for this variant (Variation ID: 542948). For these reasons, this variant has been classified as Pathogenic. -

Feb 28, 2020

Beijing Key Laboratry for Genetics of Birth Defects, Beijing Children's Hospital

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 30, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

MCCC1-related disorder

Pathogenic:1

Jan 17, 2023

PreventionGenetics, part of Exact Sciences

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The MCCC1 c.1679dupA variant is predicted to result in a frameshift and premature protein termination (p.Asn560Lysfs*10). This variant was reported to be causative for 3-methylcrotonyl-CoA carboxylase deficiency (Wu et al. 2019. PubMed ID: 31901042; Liu et al. 2021. PubMed ID: 34539730). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Frameshift variants in MCCC1 are expected to be pathogenic. This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

0.55

Mutation Taster

=3/197

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over